# Forums

## How many solar panels will there be required at a supercharger location to generate enough energy to charge 100 Model S per day?

And where exactly will they be put?
On the roof of the supercharger parking lots?
How much space will there be needed to install all these solar panels?
Does any of the existing supercharger locations already have enough solar panels installed to generate enough energy on its own?

risingsun | June 22, 2013

42

TeslaRocks | June 22, 2013

If solar constant is 1000W/m^2, assume PV efficiency of 20%, and on average 12 hours of sunlight per day, 365 days a year. That's 1000*.2*12*365 Wh or 876 kWh of electricty per year per m^2. I don't know how much energy a model S takes per charge on average, but if you find it, just divide 876 by the average charge per car and you will know how many cars that square meter of PV panel can charge a year.

tes-s | June 22, 2013

If we take your 876 number and divide it in half to get a more realistic 6-hours average sunlight per day, that is 438kwh.

Tesla says 1/2 charge (42.5kwh) in 20 minutes.

I calculate 10 of those charges per year for every square meter of panels.

IF you want 100 per day, that would be 3,650 square meters which I believe is roughly the size of a football field.

Brian H | June 22, 2013

Also the angle of the sun lowers in early morning and late afternoon. And latitude lowers the angle as it increases. Germany gets about as much sunshine as Alaska.

Benz | June 23, 2013

The size of a football field? Wow.
The space on the roof of the canopy would be too small for sure.
So, where will they put/install all these solar panels?

MBCMDR | June 23, 2013

OK my house was not solar friendly as West and East roof so I have 16 230watt panels on each side with 32 M215 inverter making about 40 kWh a day in WA. More in summer as starts next month see 50kWh average. I am looking to buy a new home in about three years after last child grads and have solar friendly home/carport garage with the slant roof to boot for solar. Here is my SOLAR over view https://enlighten.enphaseenergy.com/public/systems/PvhY78145

MBCMDR | June 23, 2013

Thinking about all this I would think SolarCity setting up commercial solar field remotely would be better as easier to monitor and all the power goes to the local power company of that area and would offset the cost. I could have setup a solar setup on the other property still goes to my power company PSE and would still offset my bill so one field could offset more than one SuperCharger Station in the same power company grid. I guess we will see but every solar panel installed on the station is just one less they have to do, plus add a NetMeter & Production Meter at each location my NetMeter was free but my Production Meter cost \$83.00

Koz | June 23, 2013

What is the sq. meters on Nummi's rooftop?

Benz | June 24, 2013

motesla | June 24, 2013

From personal experience having solar on my house in San Jose, CA, with a 54 panel array, rated at about 11kW, at peak in June this generates 75kWh per day, and in December at the low, about 45kWh per day. So taking an average of 60kWh per day per 11kW installed, it would take 100 x 11kW = 1100kW installed to charge 100 model S per day, assuming 60kWh charge for each one.

Depending on the geographic location (Lat and Long), this will also vary considerably, but taking my same panel to kW example, this would require the installation of 5400 panels.

I don't have a good idea how manys panels can fit on the roof of the supercharger covers, but maybe someone else can provide that.

nwdiver93 | June 24, 2013

Assumptions:

- Average charge of 50 kWh per car
- Charger efficiency of 90% so ~ 55 kWh per car

100 cars x 55 kWh per car = 5500 kWh

National annual average is ~4.5 hours sun / day

5500 kWh / 4.5 hours = 1222 kWp of panels... AC

So 1300 kWp of DC would cut it...

~4300 300w panels = ~7500 sq meters / ~80000 sq feet / 500 parking spaces

Superchargers aren't going to be seeing 100 cars/day anytime soon even the most congested... Gilroy might see 50/day

And where exactly will they be put?
Mall, Box store roof, covered parking for 500 spots or field(2 acres)

evpro | June 24, 2013

They will be installed on the otherwise unused roof of the hosting business (Starbucks, Olive Garden, Beef and Brew, etc.), or in the wasted cloverleaf space at every Interstate Exit/Entry ramp.

Benz | June 25, 2013

Does any of the currently existing Supercharger stations already have solar panels?

Brian H | June 25, 2013

Yeah, most of those with canopies.

Benz | June 25, 2013

As on top of those canopies there is too little space, therefore there do fit only a small number of solar panels.

And these small number of solar panels on the top of those canopies surely cannot provide that many kWh's per day.

Therefore, I think that surely more solar panels are required at these Supercharger locations to be able to say: "driving on pure sunlight".

By the way, how many solar panels are fitted on top of the canopies?

And how much kWh's can these small number of solar panels produce per day?

Mark22 | June 25, 2013

Where is the 100 car/day assumption coming from?
That is a wildly large number, even for the peak days of Friday and Sunday at the busiest stations.

Would love to see some actual numbers of use.

Benz | June 25, 2013

@ Mark22

At the moment this 100 car/day assumption might not be that accurate.

But every day more Tesla Model S's are being delivered to customers in the US, right?

Don't you think that this 100 car/day assumption will be accurate very soon (in 2013)?

Benz | June 25, 2013

On the homepage of the US website of Tesla Motors we can see the solar panels on the roof of a canopy with 4 Tesla Model S cars parked underneath it, while there are 5 parking spaces underneath the canopy (the parking space on the left side is empty).

I have counted the solar panels on the roof of the canopy. There seem to be 100 solar panels on the roof of the canopy (5 x 20).

How many kWh's can these 100 solar panels produce per day?

nwdiver93 | June 25, 2013

@Benz

The canopy pictured on Teslas' homepage would produce ~150 kWh / day

I have a 1300 sq ft house w/ 42 panels on it and I produce >60 kWh /day. I produced more than enough power so far this year for my house and car; and that's with driving >13000 miles

Like it or not... the ICE age is ending :)

Benz | June 26, 2013

@ nwdiver93

I have asked these questions just because I want to find out how Elon Musk is going to realise the claim "Driving on pure sunlight" (which is fantastic/awesome/super). I already know that Elon Musk is somehowe going to turn it into reality, that is out of the queation. But how is he going to do it? That is my point.

Nobody on this planet will be more happier than me when the ICE age will end. I am in favour of EV's (Tesla + other brands), the sooner they replace all the ICE cars on this planet the better. Let that be clear. Read my other posts on this forum. Brian H and other members of this forum know that.

You have mentioned: "The canopy pictured on Teslas' homepage would produce ~150 kWh / day".

That would mean that these 100 solar panels would generate just about enough power per day to charge only 2 Tesla Model S's (75 kWh per Tesla Model S). And that is surely not going to be enough. I can tell you that.

Brian H | June 26, 2013

Solar City is in charge of the solar generation, and can integrate arrays across the network, at least in a financial sense, to make it balance out and produce a profit. That's their business and expertise. Trying to parse each station for them is a waste of time.

Roamer@AZ USA | June 26, 2013

I run three Sunny Boy 7000 inverters and 117 panels.

Covers more than all my residential loads and charges two Leafs and One Tesla S.

I suppose if I used a super charger I am just taking back a little of the surplus I put on the grid. Based on that I still run 100% from the sun.

TeslaRocks | June 26, 2013

Following up on Koz's question (June 23), I would suggest that Tesla could consider having Solarcity install solar panels on the entire roof of Nummi, and for sure they will be able to say for a long time (until factory getting near full capacity, perhaps, if not forever) that Tesla vehicles not only can run on pure sunlight but are also made from sunlight. Sounds financially feasible, from what I read, although I appreciate that the devil is in the fine print or the details. Either way, if Tesla can pull it off, that's a claim that any major automaker will not be able to match for a long time, perhaps.

Another thought about the Nummi Tesla factory, I've noticed on Google maps nearly a year ago that there are lots of vehicles parked in files in the back (north east), waiting to be loaded onto rail cars, except that they don't look like any car Tesla is making currently, maybe Rav4 or Model X (which is of course not yet in production). Could it only be an old picture? I wish I could find it for you, but last time I searched I had trouble finding it and I don't think I could post a link of it even if I found it. I doubt it, but maybe someone knows.

Benz | June 26, 2013

@ Brian H

So, there will not be a football field covered with solar panels next to each Supercharger station, right?

Instead Solar City is going to take care of the generation of solar power elsewhere (far away from the Supercharger locations), right?

Elon Musk did mention in the conference call that each Supercharger station will cost about \$300,000. And a certain part of that amount will be spent on solar panels, right?

If Solar City is going to take care of the generation of solar power for all the 200+ Supercharger locations, that would mean that quite a significant amount will be spent on solar panels. That would result in a huge solar power plant, right?

Brian H | June 26, 2013

Not sure who covers the installation of the solar panels, but the ongoing costs and revenues are designed to give Solar City a net profit. That's all that's required.

Benz | June 27, 2013

@ Brian H

I just listened to the Conference Call of the Supercharger Announcement again. And I heard Elon Musk say that the cost per Supercharger would be about \$150,000 without Solar, and about \$300,000 with Solar. That would mean that if we would make a rough calculation we could say that for 200 Supercharger locations about \$30,000,000 will be invested by Tesla Motors in Solar Technology to generate power from pure sunlight. For \$30,000,000 you can buy a lot of solar panels, I can tell you that. That would make a huge Solar Power Plant. That would be fantastic.

Brian H | June 27, 2013

A lot of small arrays is better, in this case. More robust and flexible.

Benz | June 27, 2013

@ Brian H

OK. So, you think it would be better to not have one huge Solar Power Plant. And instead have an array of solar panels at each Supercharger Station. Right?

But still, the canopy with the solar panels on the roof of the canopy, that doesn't cost \$150,000 right?

Brian H | June 27, 2013

I don't know what the costs of a canopy of panels are. Ask Elon.

nwdiver93 | June 27, 2013

The canopy on Teslas homepage is ~30kWp. The median installed price of solar is ~\$5/w so \$150,000 for the canopy is about right.

RZippel | June 28, 2013

Funny what is expected of Elon. Let's assume 1 Billion cars worldwide (surpassed 2011) all are electric. And need one charge a day. And the above is correct for an average over all urban regions on the planet. Then you would need about 3,5 * 10^12 m^2 to charge them. One estimate for global roof space is 3,8 * 10^11 m^2 (if Hashem Akbari, Surabi Menon and Arthur Rosenfeld did estimate that right in their paper Global cooling: increasing world-wide urban albedos to offset CO2). So even all roofs of the world would only deliver a tenth of the required energy. So the "big" solution requires something else than roofs with solar panels.

I think we can allow someone else to come up with that solution, Elon doesn't have to save the world all alone, right ;-)

eDave | January 19, 2015

Having solar canopies at superchargers is certainly good PR optics for Tesla, and a good step towards 'driving on sunlight', even if, by themselves, they don't provide all the power to charge cars that come to the SC.

To really get to the goal of net-zero, I see the sum of 3 components:
1) Supercharger solar canopies
2) Residential solar for Tesla owners (owners would need to provide data)
3) Tesla Owners Solar Co-Op - Large PV arrays in optimal geographic areas that sell back to the grid to offset the balance of #1 & #2 above. Economy of scale. This would be paid for by Tesla owners (and even non-Tesla owners) in collaboration with Tesla & Solar City. Would be good for those of us who don't have the option of putting solar on our residential roof or don't live in a climate conducive to solar. Members get one-time tax credit and dividend from selling power back to the grid. Could start by building parking lot canopies at NUMMI & Gigafactory.

Brian H | January 19, 2015

Even somewhat distant solar farms and arrays can be "tied" to SCs. Elon has committed to annual surplus once they're emplaced.

spareemma | February 11, 2015

Its a quick and reliable solution for finding optimum tilt angles - > http://gogreen.inplix.com/solar-angle-calculator/

elephant in a bottle | February 11, 2015

Call this idea dumb or whatever... here goes ... Are solar panels designed horizontal only i.e. for rooftops?

Why can't they design solar panels vertically? Perhaps teepee-styled ..
This is to augment SC solar canopies, or maybe good for congested areas , where putting on building-tops is not an option.

Brian H | February 11, 2015

Any angle you want, but the sun isn't going to adjust for you.